Mineral oil composition



iatented ug. 5,

MINERAL OIL COMPGSITION Howard|` D. Hartough, Pitman, N. J., assignor toSocony-Vacuum Oil Company, Incorporated, a corporation of New York NoDrawing. Application July 1, 1948,

Serial No. 36,450

i claims. *(ol. 25e-48.2)

The present invention relates to the stabilization of hydrocarbonmixtures, and, more particularly, to the stabilization of hydrocarbonmixtures by incorporation therein of formaldimines. It hasbeen foundthat formaldimines effectively stabilize hydrocarbon mixtures tooxidizing agents when added, in amounts ranging from about one part per5000 to one part per 50 by Weight, to the hydrocarbon mixture,particularly petroleum stocks. The lower range of effectivevness asdetermined in the bubble test would indicate' that the formaldiminesprobably act as a metal deactivator.

A formaldimine is a compound having a composition corresponding to theformula, RCHzN--CHz Where R is a compound capable of participating inthe Mannich reaction. F. F.

VBlicke ,has deiined the compounds capable of participating in theMannich reaction as compounds having at least rone hydrogen atom ofpronounced reactivity (Organic Reactions kvolumeL page 304, Wiley(1942)). Blicke enumerates as compounds capable of participating in theMannion reaction, ketones, aldehydes, acids and esters, phenols,acetylenes, alpha-picolines and quinaldines. The preparation offormaldimines and the isolation thereof has, so far as it is known, notbeen described prior to the description provided in the copendingapplications for United States Letters Patent Serial No. 782,962, ledOctober 29, 1947, now Patent No. 2,577,191, patented Dec. 4, 1951, inthe name of Howard D. Hartough and Serial No. 781,754, filed October 23,1947, in the names of John W. Schick and Howard D. Hartough.

The formaldimnes are prepared by reacting a compound, as characterizedby F. F. Blicke, having at least one hydrogen atom of pronouncedreactivity with aqueous formaldehyde solution and ammonium chloride. Ingeneral, the reactants were mixed, the reaction mixture warmed toinitiate the reaction (the reaction isusually initiated at temperaturesof the order of about 70 C.) and maintained at temperatures of about "vto about 65 C. until the reaction is substantially complete and thencooled to ambient temperatures. 4 The reaction mixture is thenneutralized withstrong aqueous sodium hydroxidev or similar base and theneutralized reaction'miX- ture extracted: With a solvent, say ether andthe formaldimine recovered in any suitable manner.

When compounds, such as thiophene and thiophene derivatives, having bothof the alpha positions unsubstituted, are used as starting materalsk inthe preparations of formaldimines a second compound, also useful instabilizing hydrocarbon mixtures, is obtained. This second product has acomposition corresponding to the formula: H2C=NCH2RCH2N=CH2 where R is acompound having two hydrogen atoms of pronounced reactivity.

EXAMPLE N (2 thenyhformaldimine prepared as described in copendingapplication Serial No. 782,- 962was tested for its eectlveness in .thewellknown bubble test using an acid reiined highly parafnic oil. Thebubble test has been described inU; S. Patent No. 2,361,353 andcomprises 4placingv a section of. a cadmium-silver, alloyi surfaceweighing about 6 grams in about 30 grams .of oil and similarl sections.of the. alloy in about 30 grams of the test olcontaining variou'samountsof the material to be tested. The samples of cone trol oil and blendswith the `alloy sections 4are heatedA to, and maintained at about 175 C.for 22 hours while a stream of air is bubbled; against the alloysurface. The loss in Weight of the alloy section is a. measure of theeiectiveness ofzthe material being tested. The effectiveness of N (2thenyhformaldimine is indicated by the following tabulation: Y Y 'I fTable I Percent Weight Concentration of N- Inhbited OH' Original H 2 hAlloy Loss Alloy Loss t enyDformaldimine 1n Test 011 Miuigmms MHHgm-ms'o as o as Vo v:n 21 M16 In a similar manner a mixture containing about5013er cent N- (2-thenyl)formaldimine and about per centdi-2,5-(methyleneiminomethyl) thiphene, HzC=NCH2-,C4H2S\-CH N=CH2Q` WBStested for effectiveness. lThe 'minture'iis also eective as is manifestfrom a study' of the data presented in Table II.

Table II Percent Weight Concentration of Mixture in Test il lizggss" Ahighly paname on o: s. A. acostada and suitable for use as an automotivecrankcase oil was used as a blank or control oil and blends containingthe concentrations of N (5methyl2 thenyDformaldimine trimer indicatedin'the following tabulation subjected to the same bubble test with theresults indicated therein. It will be noted 'that the 4loss of weight bythe bearing under the test conditions decreases with decreas- Acomparison of the viscosity before test with that after test provides amathematical value oi.' the increase in viscosity.

N-(Z-thenyDformaldimine and a mixture containing approximately 70 percent of 2.5-di- (methyleneiminomethyl)thiophene and 30 per centN(2-thenyl)formaldimine were subjected to the catalytic oxidation testdescribed hereining the concentration of the trimer. before. The resultsare tabulated in Table III.

Table III (onten. N N Perntin' ma I8 O11 Cles Additive in Oil, afterViscosity Sludge Los:

AWeight 40 hours alter 40 in Mg.

percent hours -N5 2ftheny1)vforma1d1miue 1.o 6.a 29. 2 nu 229.2 7 nV2,5di-methyle-.neimino y methyDthiophene 1.0 1.8 10.7 nil 61.4 N(2thenyl)iormaldixnine 0. 25 4. 5 32. 2 nil 335. 6 None l 1.5.-() 200.0nil 200. 0

1 The blank or control was a lubricating oil oi parailinic origin oiSAE'lO grade and useful as an automotive crankcase oil.

The control oil had an initial fviscositycyonds at Percent WeightConcentration in Highly Rened Paranic Oiloi SAE 20 grams 'To furthertest the effectiveness of N-(2-thenyD'formaldimineand mixtures ofN-(2-thenyl) formaldimine and di2,5 (methyleneiminometh- -yl)thiophene,theV additives in oil were subjected to acatalytic oxidation test. Thecatalytic oxidation test is performed in the following manner:

Twenty-five milliliters ofthe oil .to be tested are placed in a'steaxnemulsion test tube -which has a capacity of 50 milliliters and isgraduated in 1 milliliter divisions.y Into the `test tube are`introduced *the following catalysts: 15.6 square inches.ofsandblastediron of analytical purity; 10.17 square inch of lead; 0.87square ixclof laluminum and 0.78squareinch of polished electrolyticcopper. The aluminum is- 99 per cent 'pure and r`is polished' in ytheVsame manner as the copper. The iron, copper and' aluminum are allwashed in A. S. T. M. naphtha and allowed to dry just before beingplaced in the test tube. Prior to testing, the lead is polished byrubbing with a cloth Wet with carbonY tetrachloride. A straight glassair inlet tube is placed in the vtest tube through the center of theiron coil so that its end, which-is Abeveled to permit the Yfree escapeof the air,'rests Yon the bottom of the ,test tube. v

Y Aglass cap, with a hole in it for the air inlet tube.' covers thecell. Before a test the glass cap air inlet tube and test tube areplaced in a potassium dichromate-sulfuricacid cleaning solution for atleast' ten minutes, washed with` tap water, then with distilledwater,.and iinally dried with acetone to ensure clean test tubes.

The oxidation cell is Vthen filled with the oil or oil Yblend to betested and heated to an aluminum-block bath at 260 F. (11 F.) for fortyhours with an air flow through the sample at ten liters per hour.

Dry air enters a Amanifold system from which it is metered to thesamples on test.

At the conclusion of the test the neutralization` number, kinematicviscosity, sludge and ieu iny weightotthelead lsection aredetermined.

It will be Ynoted that the presence of either Beilrihndsfss 25 theformaldimine alone or the 2,5-di-(methyleneiminomethyDthiophene improvedthe resistance of the oil to oxidation.

A lhighly'paraiinic automotive crankcase: oil of SAE 10 grade mixed withN-(5xnethyl=2 thenyl) formaldimine trimer in concentrations as indicatedhereinafter was subjected to .the same catalytic oxidation test withtheresults lgiven in the following tabulation:

Blends of 'N- (.p-methoxybenzyl) formaldimine trimer in a highlyparaillnic oil of SAE 10 grade were subjected to the same catalyticoxidation test with the lresults tabulated hereinafter.

4Table V Per() t Per Cent Weight Con- N. N. Increasanin Leadcentratiomoi Trimer Ai'teriO Viscosity Sludgel Losa Hours t 1.o v10.564.5 11 o oofcontroi) 12.5 215.0 11

N' (2`thenyl) formaldimine 4was subjected to lthe Lauson OxidationStability Test.

The Lauson Oxidation Stability Test has `as its purpose a determinationof oil deterioration primarily indicated by corrosion of copper-leadbearings .and secondarily by engine cleanliness. ThelLauson engine is asingle cylinder, '4 cycle liquid cooled internal combustion engineuiting*- gasoline as fuel; having splashV lubrication and a 'copper-leadbearing. 'The-engine under test conditions is operated with anoiltemperature ci' about 270". FL; a cooling jacket temperature voiabout 212 'F.,y a speed of'about A1825 R`. P.M. at one haii.' throttleand at V9.13.0-1 air-fuel ra'- tio. `The test period isr about 10o hoursand the engine ls'mspected scimmie crappmmmeiy 5 20 hours. The bearingWeightloss, engine cleanliness and'used oil analysis (neutralizationnumber, N. N.) are reported for each inspection. A blank oil usually anautomotive crank case lubricating oil of parainic origin equivalent toan SAE 20 and having a Saybolt Universal viscosity of about 318 secondsat 100 F., and of 55 seconds at 210 F., is subjected to the test and thenecessary data obtained. Then the same control oil blend with theadditive to be tested is subjected to substantially the same testconditions and the necessary data obtained. The data thus obtained ispresented in Table VI.

l The blank or control oil was a highly paraffinic lubricating oil otSAE 20 grade having a viscosity (Saybolt Universal) of 318 seconds at100 F., oi 147-157 seconds at 130 F., and of 55 seconds at 210 F. anduseful as an automotive crankcase oil.

What is claimed is:

1. A mineral oil composition comprising a lubricant fraction of mineral011 and an additive in amount effective to deactivate metal with whichsaid mineral oil composition is in contact, said additive consisting ofa formaldimine selected from the group consisting of thenyl formaldiminehaving a formula R'C4H2SCH2N=CH2, wherein R is selected from the groupconsisting of hydrogen, lower alkyl groups, and the group CH2N=CH2 andmixtures thereof in which mixtures the -CH2N=CH2 thenyl formaldimine isthe predominant constituent.

2. A mineral oil composition comprising a lubricating fraction ofmineral oil and an amount of a formaldimine eiective to deactivate metalwith which said mineral oil composition is in HOWARD D. HARTOUGH.

No references cited.

1. A MINERAL OIL COMPOSITION COMPRISING A LUBRICANT FRACTION OF MINERALOIL AND AN ADDITIVE IN AMOUNT EFFECTIVE TO DEACTIVATE METAL WITH WHICHSAID MINERAL OIL COMPOSITION IS IN CONTACT, SAID ADDITIVE CONSISTING OFA FORMALDIMINE SELECTED FROM THE GROUP CONSISTING OF THENYL FORMALDIMINEHAVING A FORMULA R''C4H2SCH2N=CH2, WHEREIN R'' IS SELECTED FROM THEGROUP CONSISTING OF HYDROGEN, LOWER ALKYL GROUPS, AND THE GROUP-CH2N=CH2 AND MIXTURES THEREOF IN WHICH MIXTURES THE -CH2N=CH2 THENYLFORMALDIMINE IS THE PREDOMINANT CONSTITUENT.